The present invention relates to a process for the catalytic oxidation of alcohols to produce carboxylic acids. More specifically, the present invention relates to a process for oxidizing primary alcohols and vicinal-diols to produce fatty acids in the presence of a ruthenium catalyst and a peracid oxidizing agent.
Fatty acids have heretofore been used commercially for the manufacture of synthetic lubricants and soaps. Consequently, the market for such fatty acids has generally exceeded the ability of industry to supply these materials from their natural sources. There is therefore a substantial demand for such fatty acids, particularly those having long carbon chains.
In the past, various processes have been developed for the production of fatty acids from various related materials. It has been proposed to treat various alcohols, such as, primary alcohols, with an oxidizing agent in the presence of a catalyst, such as ruthenium and a solvent to produce the corresponding fatty acids. For example, in Berkowitz, L. M. and Rylander, P. N., J. An. Chem. Soc. 80, p. 6682 (1958), it is reported that n-hexyl alcohol was oxidized with ruthenium tetroxide in carbon tetrachloride. This reaction was reported to produce about 10% of hexanoic acid as a product. In J. Org. Chem. Vol 33, p. 53 (1968), it was reported that a primary alcohol could be oxidized with excess sodium periodate in the presence of a catalytic amount of ruthenium dioxide in water. This particular reaction was reported to produce a 40% yield of the corresponding carboxylic acid. The House and Blankley reaction is reported to be as follows: ##STR1## Obviously, the product yield in this particular instance was also extremely low when utilizing alcohols as a starting material and periodates as an oxidizing agent.
It is therefore an object of the present invention to provide a process for producing high yields of fatty acids from certain alcohols. Another and further object of the present invention is to provide an improved process for the conversion of primary alcohols to fatty acids. A still further object of the present invention is to provide an improved process for the conversion of vicinal-diols to fatty acids. Yet another object of the present invention is to provide an improved process for the conversion of alcohols to fatty acids in the presence of a ruthenium catalyst and a peracid oxidizing agent. Yet another object of the present invention is to provide an improved process for the conversion of certain alcohols to fatty acids in the presence of a ruthenium catalyst, an oxidizing agent and an inert organic solvent. Another and further object of the present invention is to provide an improved process for the conversion of primary alcohols and vicinal-diols to fatty acids in the presence of a ruthenium catalyst, a peracid oxidizing agent, an inert organic solvent and an organic or inorganic base.